From 57b59af9fb642791a155a446fe965029227ea07a Mon Sep 17 00:00:00 2001
From: Mark Rousskov <mark.simulacrum@gmail.com>
Date: Tue, 4 Jan 2022 21:57:33 -0500
Subject: [PATCH] Add note about non_exhaustive to variant_count

---
 library/core/src/mem/mod.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/library/core/src/mem/mod.rs b/library/core/src/mem/mod.rs
index 7d005666a74a6..989ec0639cd6b 100644
--- a/library/core/src/mem/mod.rs
+++ b/library/core/src/mem/mod.rs
@@ -1045,6 +1045,10 @@ pub const fn discriminant<T>(v: &T) -> Discriminant<T> {
 /// return value is unspecified. Equally, if `T` is an enum with more variants than `usize::MAX`
 /// the return value is unspecified. Uninhabited variants will be counted.
 ///
+/// Note that an enum may be expanded with additional variants in the future
+/// as a non-breaking change, for example if it is marked `#[non_exhaustive]`,
+/// which will change the result of this function.
+///
 /// # Examples
 ///
 /// ```